Staples and cartridges containing the staples adapted to be incorporated in staple-forming devices intended for use to join separated fascia such as during an operation are known in the prior art. One such staple described in U.S. Pat. No. 4,014,492 has a straight central portion and pointed L-shaped portions at the ends of the central portion. A staple-forming device closes the staple by bending the junctures of the L-shaped portions and its central portion around the edges of an anvil so that the pointed ends of the L-shaped portions can engage and gather fascia. The closed staple assumes a rectangular shape with the points on the L-shaped portions generally aligned and closely adjacent. Such use of staples can provide much gather (the word "gather" as used herein means the ability of the staple and the device that closes the staple to draw together portions of fascia), which is very desirable so that the edges of the fascia attached will be pressed together to facilitate healing. The rectangular shape of the staple, however, allows the L-shaped legs to be too easily bent apart by tension in the gathered fascia so that the holding power of the staple is not as good as may be desired.
U.S. Pat. No. 4,127,227 describes a staple and a cartridge containing a plurality of the staples for use in a staple-forming device intended to correct the problem described above. Before it is closed, the staple described in that patent has a straight central portion with curved portions attached at each of its ends, which curved portions have points at their outermost ends adapted to engage fascia. By use of the cartridge in the staple-forming device, the curved end portions are each bent closed to form a closed staple with end loops each engaged only with one portion of the fascia to be joined. The closed loops are generally aligned with the central portion so that tension in the fascia does not act through a large lever arm in the closed loops to tend to open them. While such a closed staple structure minimizes problems with tension in the fascia opening the staple, the staple and its forming process provide very little gather so that fascia fastened by such staples may not be brought together to the degree desired by use of the staple and device.